Check if email field is blank before send mail

Check if email field is blank before send mail

Hi everyone,

in order to promote my blog I created a simple form so that visitors can tell there friends to come.

It looks like this:



Visitor's have to write down at least one email of there friends.

How could I check if optional email fields (2,3,4) are not blank so the sendmail script does not bug? ("To:" field doesn't accept blanks...)

Many
thanks!!

Sébastien